#!/usr/bin/env bash

################################################################################
# Finds changed lines not covered by tests related to changed files.
#
# Usage:
#     check/pytest-changed-files-and-incremental-coverage [BASE_REVISION]
#
# This tool is not clever; it does not understand dependencies between all
# files. If "d/x.py" or "d/x_test.py" have been modified, it will include
# "d/x_test.py" in the arguments given to pytest. It will furthermore include
# "--cov=d" as an argument to pytest-cov, to restrict coverage results to
# directories containing changed files.
#
# You can specify a base git revision to compare against (i.e. to use when
# determining whether or not a line is considered to have "changed"). To make
# the tool more consistent, it actually diffs against the most recent common
# ancestor of the specified id and HEAD. So if you choose 'origin/main' you're
# actually diffing against the output of 'git merge-base origin/main HEAD'.
#
# If you don't specify a base revision, the following defaults will be tried,
# in order, until one exists:
#
#     1. upstream/main
#     2. origin/main
#     3. main
#
# If none exists, the script fails.
################################################################################

# Get the working directory to the repo root.
thisdir=$(dirname "${BASH_SOURCE[0]:?}") || exit $?
repo_dir=$(git -C "${thisdir}" rev-parse --show-toplevel) || exit $?
cd "${repo_dir}" || exit $?

# Figure out which revision to compare against.
if [ -n "$1" ] && [[ $1 != -* ]]; then
    if ! git rev-parse --verify --quiet --no-revs "$1^{commit}"; then
        echo -e "\033[31mNo revision '$1'.\033[0m" >&2
        exit 1
    fi
    rev=$1
elif [ "$(git cat-file -t upstream/main 2> /dev/null)" == "commit" ]; then
    rev=upstream/main
elif [ "$(git cat-file -t origin/main 2> /dev/null)" == "commit" ]; then
    rev=origin/main
elif [ "$(git cat-file -t main 2> /dev/null)" == "commit" ]; then
    rev=main
else
    echo -e "\033[31mNo default revision found to compare against. Argument #1 must be what to diff against (e.g. 'origin/main' or 'HEAD~1').\033[0m" >&2
    exit 1
fi
base=$(git merge-base "${rev}" HEAD)
if [ "$(git rev-parse "${rev}")" == "${base}" ]; then
    echo -e "Comparing against revision '${rev}'." >&2
else
    echo -e "Comparing against revision '${rev}' (merge base ${base})." >&2
    rev="${base}"
fi

# Find involved files.
typeset -a cov_changed_python_file_dirs
IFS=$'\n' read -r -d '' -a cov_changed_python_file_dirs < \
    <(git diff --name-only "${rev}" -- \
    | grep "\.py$" \
    | grep -v "_pb2\.py$" \
    | xargs -I {} dirname {} \
    | perl -ne 'chomp(); if (-e $_) {print "--cov=$_\n"}' \
    | sort \
    | uniq \
)
typeset -a changed_python_tests
IFS=$'\n' read -r -d '' -a changed_python_tests < \
    <(git diff --name-only "${rev}" -- \
    | grep "\.py$" \
    | sed -e "s/\.py$/_test.py/" \
    | sed -e "s/_test_test\.py$/_test.py/" \
    | perl -ne 'chomp(); if (-e $_) {print "$_\n"}' \
    | sort \
    | uniq \
)
if git diff --name-only "${rev}" -- | grep "__init__\.py$" > /dev/null; then
  # Include global API tests when an __init__ file is touched.
  changed_python_tests+=('cirq-core/cirq/protocols/json_serialization_test.py')
fi
if [ "${#changed_python_tests[@]}" -eq 0 ]; then
    echo -e "\033[33mNo changed files with associated python tests.\033[0m" >&2
    exit 0
fi

source dev_tools/pypath || exit $?

# Run tests while producing coverage files.
check/pytest "${changed_python_tests[@]}" \
    "${cov_changed_python_file_dirs[@]}" \
    --cov-report=annotate
pytest_result=$?

# Analyze coverage files.
python dev_tools/check_incremental_coverage_annotations.py "${rev}"
cover_result=$?

# Clean up generated coverage files.
git clean --force --quiet -x -- "*.py,cover"

# Report result.
if [ "${pytest_result}" -ne "0" ] || [ "${cover_result}" -ne "0" ]; then
  exit 1
fi
exit 0
